PROJECT SUMMARY To date, no real-time indicators of surgeons' attentional load and attentional resource depletion have been developed for the laparoscopic environment. This is cause for concern as high attentional load and the consequent depletion of attentional resources are contributing factors to the high risk of mistakes in the laparoscopic environment. These mistakes are more likely to occur prior to surgeons' completion of the learning curve. The objective of the present study is to validate such real-time indicators for the laparoscopic environment. Prior research indicated that blood flow velocity (BFV) of the middle cerebral arteries (MCAs) can serve as such indicator in the vigilance (detection of critical cues) environment. The detection of critical cues (information) pertaining to the patient and surgery is critical for successful surgical outcomes. Thus, the present project will assess whether BFV changes of the MCAs can serve as valid indicators of attentional load, attentional resource depletion, and performance in the laparoscopic environment. The proposed study is anticipated to result in increased patient safety, especially during laparoscopic training. Further, the results of the present study are expected to provide the foundation for the development of new laparoscopic performance metrics that can supplement the metrics currently used in simulator-based laparoscopic testing.